We propose to test the hypothesis that hemoglobin in different ligand forms, particularly oxy and deoxy, may absorb differently to polymer and other surfaces of interest to implants and cardiovascular medicine. This is expected to be important in regions of local hemolysis, which includes practically all cardiovascular implants. The adsorption properties of haptoglobin and of oxy hemoglobin-haptoglobin complexes will also be studied. The interaction of oxy and deoxy hemoglobin in purified solutions and in the presence of haptoglobin, albumin and related proteins will be studied using UV-visible absorption spectroscopy, fluorescence spectroscopy and resonance Raman spectroscopy in the transmission modes for bulk solution studies and in the total internal reflection mode for interface and adsorption studies. Radiolabeled proteins will also be used. Adsorption to solid surfaces will be studied from purified solution media, sera, and blood as a function of degree of oxygenation and concentration of hemoglobin. The analysis of colored deposits on retrieved cardiovascular devices, including artificial hearts, will be performed, based primarily on the resonance Raman spectroscopy micro area analysis technique, to test the hypothesis that these discolorations are due to heme or its by-products. If hemoglobin in its different ligand forms is indeed adsorbed differently to surfaces, it suggests a mechanism for the different to surfaces, it suggests a mechanism for the different blood compatibility behavior of materials and devices in the arterial and the venous systems.